Objective - rewrite tune with liberal artist first (7)
I believe the answer is:
neutral
'objective' is the definition.
(similar in meaning)
'rewrite tune with liberal artist first' is the wordplay.
'rewrite' indicates an anagram.
'with' says to put letters next to each other.
'liberal' becomes 'l' (abbreviation).
'artist' becomes 'RA' (Royal Academician, member of Royal Academy of Arts).
'first' means one lot of letters go next to another.
'tune' anagrammed gives 'neut'.
'l' after 'ra' is 'ral'.
'neut' next to 'ral' is 'NEUTRAL'.
(Other definitions for neutral that I've seen before include "Non-partisan in Renault" , "'Impartial, unbiased (7)'" , "In which one parks" , "Run late (anag)" , "Bland" .)